Fossil fuels such as petroleum and coal are widely used in automobiles or power plants for generating motive force or electrical power. As known, burning fossil fuels produces waste gases and carbon oxide. The waste gases may pollute the air. In addition, carbon dioxide is considered to be a major cause of the enhanced greenhouse effect. It is estimated that the world's oils supply would be depleted in the next several decades. The oil depletion may lead to global economic crisis.
Consequently, there are growing demands on clean and renewable energy. Recently, electric vehicles and hybrid electric vehicles have been researched and developed. Electric vehicles and hybrid electric vehicles use an electrical generator to generate electricity. In comparison with the conventional gasoline vehicles and diesel vehicles, the electric vehicles and hybrid electric vehicles are advantageous because of low pollution, low noise and better energy utilization. The uses of the electric vehicles and hybrid electric vehicles can reduce carbon dioxide emission in order to decelerate the greenhouse effect.
As known, a power supply (e.g. an AC-to-DC charger or a DC-to-DC converter) is an essential component of the electric vehicle and the hybrid electric vehicle. For meeting the safety regulations, the power supply is usually designed as a sealed device to achieve a waterproof and dustproof purpose. It is critical to dissipate the heat generated by the electronic components of the sealed power supply.
The power supply of the electric vehicle or the hybrid electric vehicle is usually installed on the front side or rear side of the vehicle body. The heat-dissipating system used in the sealed power supply is selected according to the installing location, the heat transfer direction and the heat generation rate of the power supply. The sealed power supply usually has an air-cooling heat-dissipating system, a liquid-cooling heat-dissipating system, or both. In the air-cooling heat-dissipating system, plural fins are formed on a surface of the power supply. The heat generated by the power supply is transmitted to the fins, and radiated to the air according to a natural convection mechanism or removed away by a forced convection mechanism with a fan. In the liquid-cooling heat-dissipating system, a cooling liquid is pumped to a seal groove to remove away the heat generated by the heat source.
However, both of the air-cooling heat-dissipating system and the liquid-cooling heat-dissipating system have the disadvantages of having large volume and occupying large installing space and are inflexible to be allocated into the power supplies according to the properties of the power supplies. For example, it is not easy to dispose the air-cooling heat-dissipating system or the liquid-cooling heat-dissipating system into a narrow installing space of the power supply. Since the installing location, the heat transfer direction and the heat generation rate of the power supply is diversified, the heat-dissipating system needs to be inclusively designed. That is, the air-cooling heat-dissipating system or the liquid-cooling heat-dissipating system is previously determined in order to dissipate the heat of the power supply. The heat-dissipating system used in the sealed power supply of the electric vehicle or the hybrid electric vehicle, however, still has some drawbacks. For example, if the installing space is changed, the heat-dissipating efficacy is insufficient or the power supply is modified, the heat-dissipating system should be re-designed and reproduced. In other words, the conventional heat-dissipating system is not cost-effective.